The invention relates to devices and methods for homogenizing solid or semi-solid compositions and for performing solid phase immunoassays on the resultant homogenate. The invention is particularly useful for homogenizing fecal samples and detecting specific analytes therein.
The invention is employed for the analysis of a class of solid and semisolid compositions which include a mixture of extractable and unextractable components. The extractable components of such compositions may include one or more soluble or particulate analytes which, when isolated, can be analyzed using prior art solid phase immunoassay technology. Within the class of solid and semisolid compositions are included fecal materials; sludges; a variety of cellular materials, e.g. ground meat and vegetable matter, biopsy and necropsy samples, sputum, and cell scrapings from various tissues; and a variety of other biological and environmental materials. A number of compositions within this class are difficult to handle because they are noxious and/or hazardous. Each of these solid and semisolid compositions may potentially contain one or more extractable analytes having clinical or commercial significance. Examples of extractable analytes include many infectious organisms, toxins, pesticide or other chemical residues, drugs, cancer markers, nutritional components, and many others.
A prior art solid phase immunoassay for detecting occult hemoglobin in fecal material is described in U.S. Pat. No. 4,427,769 (Adlercreutz). Adlercreutz describes a two step process for detecting occult hemoglobin: 1. One side of a filter paper is contacted with a sample of fecal material for absorbing occult hemoglobin and passing occult hemoglobin to an absorbant which contacts the opposite side of the filter paper; and 2. After having absorbed occult hemoglobin, the adsorbant is then transferred to an assay vessel for desorbing the hemoglobin and performing the solid phase immunoassay. Adlercruetz's process discloses a method for maintaining a separation between unhomogenized fecal material and solid phase immunological reagents. Because the fecal material of Adlercreutz's process is unhomogenized, much of the occult hemoglobin will often remain sequestered and inaccessible for analysis within the sample material. Adlercreutz's process is best employed with samples of fecal material having abundant occult hemoglobin uniformly distributed within the sample.
If a solid or semisolid sample is unhomogenized and if analyte is distributed inhomogeniously within the sample, the relative inaccessibility of analyte within the sample may render a measurement of analyte unrepresentative of the whole sample. What is needed is a device which can homogenize or disperse compositions within this class and which can analyze the resultant homogenate employing solid phase immunoassay technology. In those cases where the sample is noxious or hazardous, it would also be preferred that the sample remain isolated within the device during the assay process.